A two-person commission panel comprising Professor Snow Barlow (chair) and Peter Cochrane approved the application in a 62-page statement of reasons and a new 57-page development consent published yesterday.

The decision says Mangoola's approval will be extended by 13 months, from November 2029 to December 2030, representing eight years of mining in the new Northern Pit if production there starts next year.

MANGOOLA FILE:

Glencore and by the mineworkers' union welcomed the decision, which was criticised by environmental groups and the Australia Institute think tank, which raised the "overstatement" of benefits recognised by the planning commission.

Muswellbrook Shire Council also opposed Glencore's application, with the commission describing the council's main concerns as "rehabilitation, contamination, instability and safety associated with the final void".

The commission noted the council's concerns that "conventional mine-by-mine . . .assessment, management and mitigation" did not capture the "compounding impacts" of the mines and power stations surrounding Muswellbrook.

The commission said the extra 52 million tonnes of "run of mine" or raw coal were on top of the previously approved extraction of 150 million tonnes, with annual production capped at 13.5 million tonnes. The mine disturbance area would increase by 27 per cent, with 623 hectares added to the existing 2294 hectares, for a total to 2917 hectares.

A Glencore spokesperson said the project met "every step" of the state government's approvals process and would provide continued employment for a workforce of about 400, most from "local communities".

"We look forward to a timely execution of federal government and Muswellbrook Shire Council approvals," the spokesperson said.

CFMEU northern mining and NSW energy district president Peter Jordan said the aproval was a "a great relief to the 400 directly employed mineworkers at Mangoola mine".

"While there are conditions to work through, the commission has found the Mangoola extension to be in the public interest. It's a terrific outcome for workers and the community."

Mr Jordan said the project had strong su\pport, with 776 of 895 public submissions in favour.

"Well done to everyone who spoke up for this project and the value of coal mining jobs to our community," Mr Jordan said.

Australia Institute research director Rod Campbell said the commission had "called out" Glencore on its claimed economic benefits but still approved the mine.

"The commission ignored whether this mine is needed as the world shifts away from coal, particularly given the 91-million-tonne gap between approved production of existing mines in the Upper Hunter and how much they produced last year," Mr Campbell said.

Georgina Woods of Lock The Gate Alliance said the extension would "double the impact" of the mine.

"This is a bitterly disappointing decision for the landholders of the Wybong Valley and for Upper Hunter residents more broadly," Ms Woods said

"Mangoola mine has already severely affected the social fabric of Wybong. Allowing it to expand now runs the risk of pushing communities beyond their ability to recover.

"It's a question of resilience - given the large number of existing huge open cut coal mines in the Upper Hunter, communities and other industries are being undermined and that puts the region's long-term future in jeopardy.

"This extension has only been sought due to Glencore's greedy mining strategy which has seen it exhaust the existing resource much faster than predicted, and it is now seeking an expansion 10 years early.

"As a result, this expansion will only extend the life of the mine 13 months beyond the original approval but will basically double the impact.

"It will double the frequency of blasts, double the number of voids, add nearly a third again as much woodland clearing and nearly half again as much greenhouse gas emissions.

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